The present invention relates generally to an applicator apparatus for applying a flowable liquid treatment fluid, in either foamed or a non-foamed state, including dyes, sizings, stains or other treating fluids, across the width of a traveling substrate, including, but not limited to, webs or sheets of textile or non-textile materials, woven or non-woven or multi-stranded materials, flexible or non-flexible sheets or sheet-like materials, for example. Other examples of substrates that can be treated with a controlled flow applicator according to the present invention include knitted substrates, cross-linked cellulose, loose fiber or impregnated substrates, thin tissue substrates, carpet or other floor coverings, continuous filament substrates, or any of a wide variety of other sheet-like materials known to those skilled in the art.
The finishing of textile fabrics or other sheet-like substrates typically includes applying dyes, sizings, stains or other xe2x80x9ctreating fluidsxe2x80x9d to the fabric or other substrate. Various methods and apparatuses have been used for this purpose, including passing the substrate through an immersion bath of the treating fluid, by which the fabric or other sheet took on a significant amount of the treating fluid. In these instances, the excess fluid absorbed or adsorbed by the fabric or sheet had to be removed and properly disposed of, requiring costly, time-consuming or energy-wasting equipment and processes, such as drying or curing of the substrate, for example.
Also, the disposal of waste water is a major concern of textile mills, particularly where the waste water contains dye liquor or other environmentally harmful treating chemicals.
Further, there is a continuing emphasis being placed in textile and other manufacturing processes upon cost-effectiveness of equipment, speed of application, energy efficiency, and increased uniformity of distribution of the treating fluid. As a result, other methods of applying treating fluids to substrates have been proposed in order to eliminate or at least minimize the disadvantages associated with drying of immersion treated substrates. One common alternative technique involves the application of the treating dye, sizing or other fluid treating material in a foamed condition to significantly reduce the amount of wet pick-up by the fabric or other substrate being treated, resulting in a minimal amount of required substrate, if any, as well as reduced waste and disposal concerns.
Many conventional methods and apparatuses for applying such foamed treating fluids use a multi-feed distribution chamber or manifold to spread and distribute the foamed treating fluid and to deliver it to an elongated nozzle extending transversely across the traveling substrate, which then dispenses foamed fluid onto the substrate. Examples of this are disclosed in U.S. Pat. Nos. 4,237,818 and 4,402,200, which are commonly owned with the present invention. Specifically, U.S. Pat. No. 4,237,818 discloses an upstanding distribution chamber which flares transversely from a central collection section as the chamber extends vertically to apply the foamed treating liquor to the bottom surface of a traveling substrate. In contrast, U.S. Pat. No. 4,402,200 discloses a flared distribution chamber circumferentially mounted on a cylindrical supporting member to achieve the desired transverse foam distribution while applying foamed treating fluid from above the substrate.
In each of these prior applicators, the flared nature of the distribution chamber necessarily causes the foamed treating liquor, dye or other fluid to travel a greater distance from the inlet tube to the transverse ends of the nozzle than to the central area of the nozzle. Because foamed treating fluids degenerate rather rapidly from a foamed state back into a liquid state, these flared distribution chambers cause the foam emitted from the nozzles to be in varying states of foam degeneration along the transversely-extending length of the nozzle. In many applications, this can produce undesired side-to-side variations in the wet pick-up by the substrate and thus similar undesired variations in the treating effect on, and appearance of, the substrate. Such non-uniformity or relative lack of accurate distribution control is especially acute in distribution chambers having considerable height and width as may be required for substrates of substantial widths.
In one highly successful attempt to overcome the above disadvantages, an applicator for applying a foamed treating liquor across the flat width of a traveling textile fabric or other sheet-like substrate includes a partially arcuate housing having an arcuate interior partition wall intermediate a foam inlet port and a foam emission nozzle opening in the housing. This arcuate interior partition wall, along with the flat opposite wall, defines a distribution chamber providing a turning foam pathway from the inlet port about the curved edge of the partition wall to the emission opening. The curved outer edge of the interior wall is preferably parabolic in shape to result in substantially all foam flow paths from the inlet port to the emission opening to be of substantially the same total length. Accordingly, the foam residence time within the distribution chamber is substantially constant regardless of the flow path assumed. This causes the amount of foam degeneration to occur uniformly across the applicator, resulting in improved uniformity of treatment of the traveling fabric or other substrate. Such improved single parabolic applicator is described in detail in U.S. Pat. No. 4,655,056, which is also commonly owned with the present invention and the disclosure of which is incorporated by reference herein.
Although this improvement represents a significant advancement in the substrate treating technology, increased environmental concerns have frequently made it desirable to further minimize the volume of fluid used in treating processes, thus further minimizing residual and remnant waste water or other fluid volumes. In addition, economic and installation concerns have led to the desirability of reducing applicator sizes in order to allow such applicators to be used in existing treating equipment, whereas single parabolic applicators, such as these described in the above-mentioned U.S. Pat. No. 4,655,056, sometimes require extensive equipment modification or replacement in order to accommodate their larger heights and widths.
Also, many of such treating apparatuses are used for treating a variety of substrates having a variety of different widths, thus requiring the use of nozzle end seals when the traveling substrate width is less than the applicator width. This results in relatively deep xe2x80x9cpocketsxe2x80x9d being formed at the ends of the applicator, which can contribute to the non-uniformity (or other undesired variations) of treating fluid application. In addition, some of the foam or other treating fluid is forced to creep along the flat wall of the above-described xe2x80x9chalf-parabolicxe2x80x9d or xe2x80x9csingle-parabolicxe2x80x9d applicator in order to help feed the outer extremities of the applicator. This can also contribute to the various drawbacks associated with non-uniformity (or lack of accurate distribution control) and degeneration of foamed treating fluids.
The present invention seeks to overcome these disadvantages and further improve on the above-described methods and apparatuses for applying a fluid from a fluid source across the lateral or transverse width of a longitudinally traveling substrate. In a preferred embodiment, the present invention includes a fluid applicator with a body having a pair of spaced apart body side walls, which are preferably but not necessarily generally parabolic in shape at their peripheral or xe2x80x9cradialxe2x80x9d edges. A fluid inlet is formed in, and extends xe2x80x9caxiallyxe2x80x9d through, one of the body side walls, with the fluid inlet being in fluid communication with the fluid source. Radially outer body edge walls, which are also preferably but not necessarily arcuate in shape, interconnect the spaced body side walls on both radial outer sides relative to the fluid inlet in order to define a hollow interior fluid distribution chamber. In this preferred embodiment, the fluid chamber extends in substantially equal and opposite radial, longitudinal and lateral directions with respect to the fluid inlet, generally along a plane substantially parallel to the traveling substrate, with the fluid chamber being substantially longitudinally and laterally symmetrical with respect to the fluid inlet.
In this preferred embodiment, a plate divider or baffle member is disposed in the above-mentioned parallel plane within the interior fluid chamber and has opposite baffle side walls spaced from, and preferably substantially complementary in shape with, the body side walls. Similarly, the plate or baffle member also has plate or baffle end walls spaced from, and substantially complementary in shape with, the body edge walls. One or more support members interconnect the plate or baffle member and the body in order to hold the plate or baffle member in its spaced relationship from said body side walls and said body edge walls in order to from an annular or peripheral fluid passage therebetween.
Further, in this embodiment, a laterally elongated fluid outlet is formed in, and communicates through, the opposite body side wall on the opposite side of the plate or baffle member from the fluid inlet and is substantially longitudinally and laterally symmetrically located with respect to said fluid inlet. Thus the fluid applicator first directs fluid from the fluid inlet divergingly outwardly therefrom in the radial, longitudinal and lateral outward directions through the space between the plate or baffle member and the first body side wall, then turns the fluid and directs it through the space between the body edge wall and the plate or baffle edge wall, and then finally redirects the fluid convergingly back inwardly in the radial, longitudinal and lateral outward directions to discharge the fluid through the fluid outlet for application to the longitudinally traveling substrate. Therefore, in this preferred embodiment, the serpentine paths of the fluid from the fluid inlet to the fluid outlet are thus substantially equal in length in substantially all radial, longitudinal and lateral directions.
Thus, rather than restricting itself to one relatively large-volume applicator, the present invention also contemplates the use of one or more smaller fluid applicators in any given installation, thus providing for reductions in the size (especially height and width) of each applicator and in the total combined volume of the applicator system, when compared with a relatively large single applicator having a comparable substrate width capacity. This reduces the amount of treating fluid present in the system or assembly at any given time (and thus the amount of resultant waste), as well as making the assembly of either a single or multiple applicators more readily usable with existing equipment.
Similarly, in this regard, the use of such relatively small applicators can also reduce the total combined length of the flow path of the treating fluid through the applicator system and thus the xe2x80x9cdwell timexe2x80x9d and resultant degree of degeneration of the treating fluid therein, when compared with a relatively large single applicator having a comparable substrate width capacity. The number of such applicators used in a given installation will, of course, depend upon factors and considerations such as the available space, the type of equipment present on site, the expected range of widths of the substrates contemplated, and the required degree of accuracy of uniformity (or accuracy in a desired variation) of fluid application across the substrate, for example.
Also, in such multi-applicator installations, varying widths of substrates can be accommodated by turning off, or disabling individual applicators at transversely or laterally outer ends. This greatly reduces the amounts of concentrated treating fluid at the resultant end xe2x80x9cpocketsxe2x80x9d, again whether or not end seals are required. Such an installation can also have purge valves or bypass valves, or both, on at least the transversely outer applicators for purging the treating fluid at relatively slow flow rates or for flushing the system with a flushing fluid.
These and other benefits are provided by the present controlled flow applicator invention, regardless of whether the treating fluid is foamed or non-foamed, and regardless of whether one or a plurality of applicators are used in a given installation. Also, each applicator of the present invention can have a preferred double-parabolic shape, as mentioned above, or any of a number of alternate shapes, where such alternate shapes can provide serpentine paths of the fluid from the fluid inlet to the fluid outlet that are substantially equal in length in substantially all directions. It should be noted, in this regard, that accurately controlled flow applicators according to the present invention can also be advantageously used where pre-determined variations in the application of a treating fluid are desired or required. Such optional controlled variation of application of the treating fluid across or along a substrate can be accomplished by modulating the flow of the treating fluid (according to a numerically controlled pattern or sequence, for example) as the substrate travels past the discharge, by providing different sizes or shapes of the chambers and/or baffle members in the applicators in a pre-selected series across the substrate, and/or by providing applicators having fluid chambers and/or baffle members that are irregular in shape or that otherwise result in a predetermined non-uniform flow across their lateral widths.
Additional objects, advantages and features of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.